Recollection-related hippocampal fMRI effects predict longitudinal memory change in healthy older adults

Abstract

Prior fMRI studies have reported relationships between memory-related activity in the hippocampus and in-scanner memory performance, but whether such activity is predictive of longitudinal memory change remains unclear. Here, we administered a neuropsychological test battery to a sample of cognitively healthy older adults on three occasions, the second and third sessions occurring one month and three years after the first session. Structural and functional MRI data were acquired between the first two sessions. The fMRI data were derived from an associative recognition procedure and allowed estimation of hippocampal effects associated with both successful associative encoding and successful associative recognition (recollection).Baseline memory performance and memory change were evaluated using memory component scores derived from a principal components analysis of the neuropsychological test scores.Across participants, right hippocampal encoding effects correlated significantly with baseline memory performance after controlling for chronological age. Additionally, both left and right hippocampal associative recognition effects correlated significantly with longitudinal memory change after controlling for age, and the relationship with the left hippocampal effect remained after also controlling for left hippocampal volume. Thus, in cognitively healthy older adults, the magnitude of hippocampal recollection effects appears to be a robust predictor of future memory change.

Specific and general relationships between cortical thickness and cognition in older adults: a longitudinal study

“…Loadings for each component are given in Supplemental Table 3. It is worth noting that the outcome of this PCA differs from those described previously by virtue of the absence of a 'speed' component (de Chastelaine et al, 2019;Hou et al, 2020;, reflecting the omission of the Trails scores. The factor loadings for the remaining components were unaffected by this omission.…”

“…The benefits of this approach, along with more general issues concerning re-test effects, are discussed in detail in Hou et al (2020). We note, however, that our main findings in respect of relationships between cortical thickness and baseline performance, and of the relationships between thickness and memory change, were largely unaffected when either session 1 or session 2 scores alone comprised the estimates of baseline performance (see Supplementary materials).…”

“…Mean cortical thickness measures and session 1 neuropsychological test data were described in a prior report (de Chastelaine et al, 2019). Neuropsychological test data from all three test sessions were reported in Hou et al (2020). Here, we describe relationships between baseline IFG and mean cortical thickness measures from the left and right hemispheres, baseline neuropsychological test scores, and scores obtained at follow-up after 3 years.…”

“…Neuropsychological test scores were fully reported in Hou et al (2020). The data are however re-described in Supplemental Table 1 for the convenience of the reader.…”

A comprehensive score reflecting memory-related fMRI activations and deactivations as potential biomarker for neurocognitive aging

“…One study revealed a relationship of dedifferentiation of stimulus-specific processing in the lateral occipital cortex and parahippocampal place area and memory performance (Koen et al, 2019), but in that study, age and memory performance were independently associated with dedifferentiation (for a further discussion, see Koen and Rugg, 2019). Recently, recollection-related fMRI activation of the hippocampus during retrieval has been associated with both memory performance and longitudinal preservation of memory performance in older adults (Hou et al, 2020). While this approach will likely yield similar results to our whole-brain approach with encoding-related activation patterns, it may be limited in subjects with very poor memory performance, like individuals with subjective cognitive decline or mild cognitive impairment, especially considering that an associative word-pair learning task was used.…”